Chimeric cells of maternal origin in juvenile idiopathic inflammatory myopathies

We identified maternal microchimerism by fluorescence in-situ hybridisation in magnetically-separated CD4 or CD8 peripheral blood cells of eight of ni ne male patients with juvenile idiopathic inflammatory myopathy, compared w ith two of nine healthy male controls. We also found maternal microchimeris m in inflammatory lesions (one skin sample and nine muscle biopsy samples) of all ten patients examined, compared with two of ten biopsy samples from patients with other muscle disorders. These results suggest that maternal c ells may be involved in the pathogenesis of juvenile idiopathic inflammator y myopathy.